1 // SPDX-License-Identifier: GPL-2.0
2 /* drivers/rtc/rtc-goldfish.c
4 * Copyright (C) 2007 Google, Inc.
5 * Copyright (C) 2017 Imagination Technologies Ltd.
9 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/rtc.h>
14 #define TIMER_TIME_LOW 0x00 /* get low bits of current time */
15 /* and update TIMER_TIME_HIGH */
16 #define TIMER_TIME_HIGH 0x04 /* get high bits of time at last */
17 /* TIMER_TIME_LOW read */
18 #define TIMER_ALARM_LOW 0x08 /* set low bits of alarm and */
20 #define TIMER_ALARM_HIGH 0x0c /* set high bits of next alarm */
21 #define TIMER_IRQ_ENABLED 0x10
22 #define TIMER_CLEAR_ALARM 0x14
23 #define TIMER_ALARM_STATUS 0x18
24 #define TIMER_CLEAR_INTERRUPT 0x1c
29 struct rtc_device *rtc;
32 static int goldfish_rtc_read_alarm(struct device *dev,
33 struct rtc_wkalrm *alrm)
39 struct goldfish_rtc *rtcdrv;
41 rtcdrv = dev_get_drvdata(dev);
44 rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
45 rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
46 rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
48 do_div(rtc_alarm, NSEC_PER_SEC);
49 memset(alrm, 0, sizeof(struct rtc_wkalrm));
51 rtc_time64_to_tm(rtc_alarm, &alrm->time);
53 if (readl(base + TIMER_ALARM_STATUS))
61 static int goldfish_rtc_set_alarm(struct device *dev,
62 struct rtc_wkalrm *alrm)
64 struct goldfish_rtc *rtcdrv;
69 rtcdrv = dev_get_drvdata(dev);
73 rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
74 writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
75 writel(rtc_alarm64, base + TIMER_ALARM_LOW);
76 writel(1, base + TIMER_IRQ_ENABLED);
79 * if this function was called with enabled=0
80 * then it could mean that the application is
81 * trying to cancel an ongoing alarm
83 rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
85 writel(1, base + TIMER_CLEAR_ALARM);
91 static int goldfish_rtc_alarm_irq_enable(struct device *dev,
95 struct goldfish_rtc *rtcdrv;
97 rtcdrv = dev_get_drvdata(dev);
101 writel(1, base + TIMER_IRQ_ENABLED);
103 writel(0, base + TIMER_IRQ_ENABLED);
108 static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
110 struct goldfish_rtc *rtcdrv = dev_id;
111 void __iomem *base = rtcdrv->base;
113 writel(1, base + TIMER_CLEAR_INTERRUPT);
115 rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
120 static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
122 struct goldfish_rtc *rtcdrv;
128 rtcdrv = dev_get_drvdata(dev);
131 time_low = readl(base + TIMER_TIME_LOW);
132 time_high = readl(base + TIMER_TIME_HIGH);
133 time = (time_high << 32) | time_low;
135 do_div(time, NSEC_PER_SEC);
137 rtc_time64_to_tm(time, tm);
142 static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
144 struct goldfish_rtc *rtcdrv;
148 rtcdrv = dev_get_drvdata(dev);
151 now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
152 writel((now64 >> 32), base + TIMER_TIME_HIGH);
153 writel(now64, base + TIMER_TIME_LOW);
158 static const struct rtc_class_ops goldfish_rtc_ops = {
159 .read_time = goldfish_rtc_read_time,
160 .set_time = goldfish_rtc_set_time,
161 .read_alarm = goldfish_rtc_read_alarm,
162 .set_alarm = goldfish_rtc_set_alarm,
163 .alarm_irq_enable = goldfish_rtc_alarm_irq_enable
166 static int goldfish_rtc_probe(struct platform_device *pdev)
168 struct goldfish_rtc *rtcdrv;
172 rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
176 platform_set_drvdata(pdev, rtcdrv);
178 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
182 rtcdrv->base = devm_ioremap_resource(&pdev->dev, r);
183 if (IS_ERR(rtcdrv->base))
186 rtcdrv->irq = platform_get_irq(pdev, 0);
190 rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
191 if (IS_ERR(rtcdrv->rtc))
192 return PTR_ERR(rtcdrv->rtc);
194 rtcdrv->rtc->ops = &goldfish_rtc_ops;
195 rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
197 err = devm_request_irq(&pdev->dev, rtcdrv->irq,
198 goldfish_rtc_interrupt,
199 0, pdev->name, rtcdrv);
203 return rtc_register_device(rtcdrv->rtc);
206 static const struct of_device_id goldfish_rtc_of_match[] = {
207 { .compatible = "google,goldfish-rtc", },
210 MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
212 static struct platform_driver goldfish_rtc = {
213 .probe = goldfish_rtc_probe,
215 .name = "goldfish_rtc",
216 .of_match_table = goldfish_rtc_of_match,
220 module_platform_driver(goldfish_rtc);
222 MODULE_LICENSE("GPL v2");